System design interview question
Design a Multi-Tenant Permission and Access Control System like Okta's Attribute-Based Access Control (ABAC) at Scale
Design an enterprise-grade permission and access control system that serves 10,000+ organizations with 500M+ total users, handling 100K authorization checks per second across geographically distributed regions with sub-50ms latency requirements and 99.99% availability. The system must support dynamic attribute-based access control (ABAC) policies, real-time policy updates with eventual consistency across regions, tenant isolation with zero cross-tenant leakage, and hierarchical role inheritance. Key constraints include: policy evaluation must complete within 10ms, support for complex boolean expressions with 50+ attributes per decision, audit logging of all access decisions, and cost-efficient caching strategies that handle millions of distinct policy configurations.
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